FC13/KDE
I having problems with jackd not starting, because it can't find a backend
Which one do I use pulseaudio or alsa ?
There is no output in /var/log/messages for jackd.
Here is the output of running "jackd"
$ jackd
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
usage: jackd [ --no-realtime OR -r ]
[ --realtime OR -R [ --realtime-priority OR -P priority ] ]
(the two previous arguments are mutually exclusive. The default is
--realtime)
[ --name OR -n server-name ]
[ --no-mlock OR -m ]
[ --unlock OR -u ]
[ --timeout OR -t client-timeout-in-msecs ]
[ --port-max OR -p maximum-number-of-ports]
[ --debug-timer OR -D ]
[ --no-sanity-checks OR -N ]
[ --verbose OR -v ]
[ --clocksource OR -c [ c(ycle) | h(pet) | s(ystem) ]
[ --replace-registry ]
[ --silent OR -s ]
[ --version OR -V ]
[ --nozombies OR -Z ]
-d backend [ ... backend args ... ]
Available backends may include: alsa, dummy, freebob, firewire, net,
oss, sun, or portaudio.
jackd -d backend --help
to display options for each backend
[mickey@Acer ~]$ jackd -d backend --help
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
jackd: unknown driver 'backend'
# jackd -d pulseaudio
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
jackd: unknown driver 'pulseaudio'
[root@Acer mickey]# jackd -d alsa
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
control device hw:0
the playback device "hw:0" is already in use. Please stop the
application using it and run JACK again
cannot load driver module alsa
There are no other applications using the sound system.

Do you have pulseaudio running? If so, stop it first, then run jackd -d
alsa. You'll probably also need to make some config file changes, but
jackd will tell you what to change. I'm still trying to learn this stuff
myself.
Regards,
John

[root@Acer mickey]# jackd -d alsa
jackd 0.118.0
Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn
and others.
jackd comes with ABSOLUTELY NO WARRANTY
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details
JACK compiled with System V SHM support.
loading driver ..
creating alsa driver ... hw:0|hw:0|1024|2|48000|0|0|nomon|swmeter|-|32bit
control device hw:0
the playback device "hw:0" is already in use. Please stop the application
using it and run JACK again
cannot load driver module alsa
There are no other applications using the sound system.

Have you tried starting jackd just after login? Even if an application is
not making any audible sounds it can still using the sound card. firefox
does this.
Also I think you need to edit your /etc/asound.conf file to set up jack
properly. I haven't been able to get this to work properly either. I can get
jark started and running ok, but then I can't get it to make a sound.
Sam